title: Does vitamin D3 supplementation improve glucose homeostasis in overweight or obese women? A double-blind, randomized, placebo-controlled clinical trial.
abstract: OBJECTIVE
  Vitamin D deficiency is considered as a risk factor in cardiometabolic disorders, including cardiovascular diseases, hypertension and Type 2 diabetes mellitus. We have investigated the effect of vitamin D3 supplementation on glucose homeostasis in healthy overweight and obese women.
  
  
  METHODS
  In a double-blind randomized placebo-controlled clinical trial, 77 healthy overweight or obese women (mean age 38 ± 8 years; BMI 29.9 ± 4.2 kg/m(2)) were randomly assigned to the vitamin D3 group (25 μg/day as cholecalciferol tablets) or the placebo group. Selected anthropometric indices, glucose, insulin, HbA(1c) and homeostasis model assessment of insulin resistance at baseline and after 12 weeks were measured. Dietary intakes using 24-h food recall and food frequency questionnaires were assessed. Physical activity was assessed by the International Physical Activity Questionnaire. Adjusted mean differences were calculated using analysis of covariance. Correlation coefficients were calculated by Pearson's analysis.
  
  
  RESULTS
  Mean fasting blood glucose concentrations declined in the vitamin D3 and placebo groups (-0.28 ± 0.4 vs. -0.65 ± 0.4 mmol/l, P < 0.001) and the mean percentage of HbA(1c) was decreased (-13 ± 18 vs. -19 ± 17 mmol/l, P = 0.06) in both groups, respectively. Mean 25-hydroxyvitamin D concentrations increased in the vitamin D3 and placebo groups (38.2 ± 32 vs. 4.6 ± 14 nmol/l, P < 0.001), respectively. There was a significant correlation between HbA(1c) and 25-hydroxyvitamin D concentrations (r = -0.271; P = 0.018).
  
  
  CONCLUSIONS
  The results indicate that the vitamin D3 supplement of 25 μg/day had no beneficial effect on glycaemic indices in healthy overweight or obese women.
authors.affiliation: Department of Nutrition, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Salehpour
authors.forename: F
authors.initials: F
authors.lastname: Shidfar
authors.forename: F
authors.initials: F
authors.lastname: Hosseinpanah
authors.forename: M
authors.initials: M
authors.lastname: Vafa
authors.forename: M
authors.initials: M
authors.lastname: Razaghi
authors.forename: F
authors.initials: F
authors.lastname: Amiri
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D002762:Cholecalciferol / Q000627:therapeutic use*; D015930:Diet Records; D019587:Dietary Supplements; D004311:Double-Blind Method; D004435:Eating; D015444:Exercise; D005260:Female; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D009765:Obesity / Q000097:blood / Q000150:complications / Q000178:diet therapy*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000178:diet therapy*; D014815:Vitamins / Q000627:therapeutic use*
chemical_list: D001786:Blood Glucose; D014815:Vitamins; D002762:Cholecalciferol